The objectives of the proposed studies are as follows: a. Characterize cell wall proteins of gonococci to determine qualitative or quantitative differences between LA plus LA minus organisms. b. Determine the interactions between gonococcal cell wall proteins and human leukocytes. c. Determine whether interactions of gonococci with leukocytes are influential as determiners of virulence of these organisms in chicken embryos. d. Elucidate differences in behavior of P plus and P minus gonococci inoculated into chick embryos that might account for the differences in virulence characteristic for these organisms. e. Study "host" factors that might influence susceptibility of chick embryos to infection and killing by gonococci. f. Discover the ultrastructural consequences of action of several different chemicals (saponin, filipin, trypsin, phospholipase, long chain fatty acids, and phospholipids) and systems (antibody plus complement) on the gonococcal cell wall. g. Determine the influence of antibodies directed toward several gonococcal surface components including pili on interactions between gonococci and tissue culture cells. h. Determine the nature of material responsible for "toxic" affects of gonococci or gonococcal products on tissue culture cells. i. Determine whether gonococci or their products stimulate chemotaxis of human neutrophils. j. Study the genetics of pilation of gonococci more extensively.